Multiaddressing with MAST

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Multiaddressing with MAST

• SAINT 2004, Tokyo
• D. Crocker
• Brandenburg InternetWorking
• http//brandenburg.com/current

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Multiaddressing

• IP
• Independent datagrams
• Infrastructure works fine
• Long time to get that way
• Leave it alone!
• Multiaddressing
• Multiple IP Addresses
• Association of datagrams
• Like transport context
• Like IP routing choice

Multihomed
Renumber
3
MAST

• Multiple Address Service for Transport
• Pools of locators, for pairs of endpoints
• Protected control channel, for maintenance of
  pools
• Identify association with TCP-like Association
  ID
• Peer-to-Peer No infrastructure needed for core
  service!
• Add third-party components when essential
• Mobile client Standard transport rendezvous
• Mobile target Dynamic presence service
• Endpoint surrogate Forwarding agent (NAT-like)

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MAST Architecture
EP Endpoint TR Transit EID Ephemeral
IDentifier
Transport
Transport
IPf
IPq
IP-TR
IP-TR
IP-TR
IPf
IPq
IPy
IPa
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MAST Protocol

• Pool maintenance
• Send complete locator list, to avoid
  synchronization problems
• Send PROBE to peer, to discover your own NAT
  public address
• Security only equal to current IP
• Domain Name, as registered, global identifier
• Nonce, internal to association for context
  reference, anti-hijacking
• Design the nonce and channel scheme for desired
  protection
• Efficiencies
• MAST is not in critical path of transport
  startup(!)
• Can even defer MAST until association is
  persistent
• However separate MAST channel adds to packet
  overhead

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SLAPShared Locator Address Pool

• Multiple transports
• Cooperative
• Reduce packet overhead
• Share on sets of attributes
• Issue
• Synchronizing changes between different control
  paths

Assoc-ID EIDl, EIDr,(IPl1, IPr1), (IPl2,
IPr2), A1, A2,
SLAP
TCP
mTCP
SCTP
MAST
IP-TR
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Evaluating Design Choices

• Features
• Multiaddressing
• Multihoming, mobility, both
• Infrastructure
• None, sometimes, always
• IP version(s)
• Identifier
• Registered vs. ephemeral
• Rendezvous
• Creating the association
• After service interruption

• Overhead
• Per payload packet
• Control protocol
• Transport startup delay
• Scaling impact
• Constant per association, vs. deferred
• Administration